I am kinda new here and I want to start a new project based on Arduino UNO. I want to control 3 leds or 3 relays( I don't know so far) from my computer via USB->Arduino UNO. I have a C program that when runs write a value in a .txt file. That value I want to be like a command for the uC: what led should turn ON.
Its something I can do with Arduino UNO?